Lubricating oil compositions for use in crankcases of internal combustion engines are well known. Such compositions may contain one or more additives to improve certain properties, e.g., additives which serve as friction modifiers, anti-oxidants, detergents, dispersants, corrosion inhibitors, wear reducing additives, and other additives.
Among the various types of internal combustion engines are spark ignition engines which are used primarily for automotive and small engine applications. Such spark ignition engines may require lubricants that contain one or more friction modifiers, wear reducing agents, and the like in order to protect engine parts, reduce engine wear, and/or improve fuel economy. Certain friction modifiers and metal-containing compounds or combinations of friction modifiers and metal-containing compounds may be particularly useful for improving some performance characteristics of internal combustion engines while at the same time causing the formation of unwanted engine deposits. The foregoing is particularly true of molybdenum-containing compounds. At relatively low concentration levels, molybdenum compounds may contribute to an increase in engine deposits. At relatively high levels, molybdenum compounds are more effective for improving fuel economy but may contribute substantially more to the formation of higher levels of unwanted engine deposits. Accordingly, what is needed is a lubricant composition that not only improves fuel economy, but also does not contribute higher levels of unwanted engine deposits.
In view of the foregoing, exemplary embodiments of the disclosure provide a lubricant composition, lubricant concentrate and method for reducing engine deposits. The composition and method include a base oil of lubricating viscosity; an organo-molybdenum compound providing about 400 ppm or more molybdenum metal by weight to the lubricant composition based on a total weight of the lubricant composition; a deposition reducing amount of a reaction product of an alkyl-substituted dicarboxylic acid compound selected from the group consisting of alkyl-substituted dicarboxylic acids, alkyl-substituted dicarboxylic acid anhydrides, and mixtures thereof, and a basic salt of aminoguanidine, in an amount sufficient to provide a product rich in alkyl bis-3-amino-1,2,4-triazole; and optionally a phenate detergent. The lubricant composition and method provide engine deposits that are less than an amount of engine deposits in the absence of component (c) and/or optional component (d).
In another embodiment, the disclosure provides a deposit reducing additive concentrate for an engine crankcase lubricant that includes an organo-molybdenum compound; a deposition reducing amount of a reaction product of an alkyl-substituted dicarboxylic acid compound selected from the group consisting of alkyl-substituted dicarboxylic acids, alkyl-substituted dicarboxylic acid anhydrides, and mixtures thereof, and a basic salt of aminoguanidine, in an amount sufficient to provide a product rich in alkyl bis-3-amino-1,2,4-triazole; and optionally a phenate detergent.
The disclosure also provides a method for reducing deposits in an internal combustion engine. According to the method, an engine is lubricated with a lubricant composition that includes lubricating an engine with a composition that includes a base oil of lubricating viscosity; an organo-molybdenum compound; a deposition reducing amount of a reaction product of an alkyl-substituted dicarboxylic acid compound selected from the group consisting of alkyl-substituted dicarboxylic acids, alkyl-substituted dicarboxylic acid anhydrides, and mixtures thereof, and a basic salt of aminoguanidine, in an amount sufficient to provide a product rich in alkyl bis-3-amino-1,2,4-triazole; and optionally a phenate detergent. The lubricant composition provides engine deposits that are less than an amount of engine deposits in the absence of component (c) and/or optional component (d).
A further embodiment of the disclosure provides a lubricant composition for reducing engine deposits. The composition and method include a base oil of lubricating viscosity; an organo-molybdenum compound providing less than about 400 ppm molybdenum metal by weight to the lubricant composition based on a total weight of the lubricant composition; a deposition reducing amount of a reaction product of an alkyl-substituted dicarboxylic acid compound selected from the group consisting of alkyl-substituted dicarboxylic acids, alkyl-substituted dicarboxylic acid anhydrides, and mixtures thereof, and a basic salt of aminoguanidine, in an amount sufficient to provide a product rich in alkyl bis-3-amino-1,2,4-triazole; and optionally a phenate detergent. The lubricant composition and method provide engine deposits that are less than an amount of engine deposits in the absence of component (c) and/or optional component (d).
As described in more detail below, the disclosed embodiments may be effective for reducing engine deposits, particularly deposits associated with turbocharger bearings, while at the same time maintaining improved fuel economy by allowing the use of higher amounts of organo-molybdenum compounds. The results of using the additive component rich in alkyl bis-3-amino-1,2,4-triazole alone, or in combination with a phenate detergent are surprising and quite unexpected. Further features and advantages of the disclosed embodiments may be provided in the following detailed description.